In a Fiber-to-the-Distribution Point (FttDP) system each remote node (Access Network Unit—ANU, also known as Distribution Point Unit—DPU), which provides the interface between the optical domain and the wired electrical connection into the customer premises, may be powered from an electricity supply located in the customers' premises, using the wired electrical connection. Several customers may be connected to the ANU and each could be operating under different power sink conditions depending upon the services that each customer is consuming.
International Patent specifications WO2009/138710, WO2009/138711, and WO2010/082016 describe a power supply system in which the power supply to be delivered by each user connected to an ANU is controlled such that users connected over short drop lengths provide proportionately more power to the ANU than those connected over longer drops. This reduces energy losses, because of the lower power losses on shorter (lower resistance) electrical connections (Power loss=I2R, with R (resistance) proportional to the length of wire through which the current passes).
The reduced power draw on the longer connections also compensates those customers on the longer connections for the generally slower DSL service possible over the longer lines. However, the system described in the earlier references was isolated from the element management of the ANU and the state of the CPE (battery backup).
It is common for the ANU or distribution point to be located in a relatively inaccessible location such as on a pole, or in a locked curbside cabinet, and only accessible to trained and authorized personnel of the telecommunications service provider. It is therefore not practical to make adjustments to their settings manually, so a setting procedure is required that can be operated using control signals transmitted from a remote location.
When a connection is operational, signaling between the customer premises equipment and the ANU can be achieved using a management channel in the xDSL (digital subscriber line) protocols. However, at system start-up or following an interruption in connection there is no xDSL operating, and therefore no means of controlling the power collection function. Without power, the xDSL protocols cannot be used to communicate with the customer premises equipment to initiate the power collection function.